The present invention relates to a head for an iron type golf club.
In order to increase the moments of inertia around the axes of the club head which pass through the gravitational center thereof, and are horizontal and vertical to the lined face grooves thereof, a conventional iron type golf club head is arranged as described and shown in, for example, the Japanese Patent Application Opening Gazette No. 63-27986 and the Japanese Utility-Model Application Opening Gazette No. 62-92857. That is to say, as shown in FIG. 9 illustrating such prior art, a rear portion b of a club head is reduced in the thickness of the middle portion thereof to form a recessed portion a therein, and the material corresponding in quantity to the reduced thickness of the rear portion is uniformly applied to the peripheral portion thereof, thereby allowing the rear portion to be provided with a peripheral thicker portion c.
However, an increase in the thickness of a portion A adjacent to the horizontal axis X of the club head which passes through the gravitational center G thereof in parallel with the lined face grooves therein does not greatly contribute to an enhancement in the moment of inertia about the horizontal axis X.
On the other hand, an increase in the thickness of a portion B adjacent to the vertical axis Z of the club head which passes through the gravitational center G thereof, and is perpendicular to the lined face grooves therein is not effective for an increment in the moment of inertia, Mz about the vertical axis X.
It is therefore an object of the present invention to provide an improved head for an iron type golf club, which is sufficiently increased in the moment of inertia about each of the parallel axis thereof with the lined face grooves thereof and the vertical axis thereof to the lined face grooves, thereby allowing an increment in the area of the sweet spot thereof to diminish aberration of the flying direction of the ball when the ball has been subjected to an erroneous shot, and to prevent any decline in the flying distance of the ball.